A gas turbine engine typically includes a fan section, a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-energy exhaust gas flow. The high-energy exhaust gas flow expands through the turbine section to drive the compressor and the fan section. The compressor section typically includes low and high pressure compressors, and the turbine section includes low and high pressure turbines.
Both the compressor and turbine sections include rotating blades alternating between stationary vanes. The vanes and rotating blades in the turbine section extend into the flow path of the high-energy exhaust gas flow. Leakage around vanes and blades reduces efficiency of the turbine section. Blade outer air seals control leakage of gas flow and improve engine efficiency. All structures within the exhaust gas flow path are exposed to the extreme temperatures. A cooling air flow is therefore utilized over some structures to improve durability and performance